Wanna know who you can trust not to hurt you?
Nobody. Absolutely no one, because even with the very most compassionate, dedicated-to-trustworthiness person EVER, you're gonna get hurt. Sometimes people hurt you WHILE they are trying their damnedest to make you feel better. A person who would never hurt you would have to be not only perfectly patient, wholly accepting, eternally available, and effusively loving, but also omniscient. Not even you can predict everything that might cause you pain, and you can't possibly communicate even all that you DO know. But that doesn't mean that the correct answer is to choose to trust no one.
Instead, choose with future pain in mind. Trust people who are going to react to hurting you in a way that will not cause you further pain, and will instead help you heal. When deciding whether or not to trust someone, the most important skills to look for are honesty and conflict-management. If they can't have an argument with someone without calling names, attacking character, turning things into a blame contest of right and wrong, or cutting contact without trying to work it out first, they are not a trustworthy person. You can still love them from a distance, but if you let them close you are going to be in harms way. You can find out how good they are at conflict management by listening to how they talk about their previous relationships or anyone they might currently be in conflict with: a friend, a coworker, a family member. If they paint that person as an enemy with no redeeming qualities, keep in mind that it only takes one mistake on your part for them to treat you the same way.
I trust lots of people to varying extents. I trust the entire internet by sharing publicly, but that is not an area of vulnerability for me. For me to trust someone enough to share significant time with them (which IS vulnerability for me), I have to know that 1) if I hurt them in some way, they will let me know as kindly as they can, and give me a chance to work it out. I also have to know that 2) they will want to do better if they accidentally hurt me, and that 3) they would never deliberately cause another person emotional suffering. I consider these three things to be the basics of decent conflict-management skills. You cannot manage conflict correctly without compassion.